A May 4 wedding is being planned by Chelsea Johnston of Butler and Tommy Vaughn of Butler. The bride-to-be is the daughter of Ray and Cyd Johnston of Butler. Mother of the prospective bridegroom is Maxine Hagen of Butler. The bride-elect is a 2007 graduate of Butler High School and is a student at Slippery Rock University. She is employed by Butler County. Her fiance graduated in 1999 from Butler High School. He is employed as a truck driver in Cheswick.